An Automated Gas Filling System

A major Gas company required the conversion and updating of its gas cylinder filling systems globally. A contract to undertake this task was given to a major systems integration company "Dickinson Autocon" Pty Ltd Based in Sydney. Fast Automation was subcontracted to assist in this project.

Scope of the main project:

The main project entailed the design, development and implementation of a secure and maintainable control system, to automate the mixing and filling of gas to an unlimited number of recipes. This encompassed the electrical & software design through to commissioning. The system had to be compatible with an existing complex algorithm for filling volatile gasses. The system also had to be flexible and generically applied to widely differing filling plants without code changes.

Fast Automation’s part:

The customer supplied a URS for each plant- from this Fast Automation undertook the following:

• Process Design Specification – Containing drawings and in a very controlled syntax text for describing the Stepping logic & procedures required of the filling system
• Generation of an FDS (Functional Design Specification) - this document was extensive and contained very detailed information on every step of the process, all software functions, Graphical screen dumps, report examples, recipe structure, parameter listings etc as well as the system architecture and hardware to be used.
• Generation of SCADA Application – including, plant mimics, live device profiles, recipe handling, reports, alarms annunciation and logging, security policy, command prompts for instructing operator actions, custom auto barcode label printing software etc.
• Generation of Simulation application - to allow full simulation of the complete system off site.
• PLC Programming - Heavy monitoring and assistance in the PLC programming to the FDS & PDS including complete coding of various code modules. Setting up and testing of OMRON’s CLK DataLink network to allow PLC’s to share memory areas.
• Production of STS Software Test Specification - this contained the plan for the testing including the systems to be utilized and the methodology.
• Automation Support Document – this extensive document described how to perform future tasks such as replacing the PLC program, troubleshooting faults, rebuilding SCADA PC’s and how to configure the software for each plant.
• Commissioning of 2 early plants.
• Generation of SCR – Site Commissioning Reports to control & document the successful commissioning of each plant in a safe manner.
  

Project statistics:

The project presented a number of challenges: The Que system was very complex and required searching ahead of recipes to allow filling of the same gas to different locations to be done in parallel but only under strict conditions. SCADA requirements were unique in that the whole application changed graphically and functionally between sites but used the same code with different configuration options set – this was a very valuable synergy suggested and introduced to the project by Fast Automation. The reporting was very extensive with different levels of reports required per gas filling module, per operator, per Fill, per shift etc. The Alarm’s handling was extensive and the history sorted per logical area. Every action was monitored all control is closed loop – with a back up loop. The Recipe handling allowed for unlimited ordering of procedures and setting of procedure step parameter sub steps, but with different rules for each plant. Then the actual filling of gases that behave differently both at different pressures and different temperatures was always the main challenge of the system, the parameters of control are then all different again for each gas type! and each gas combination. For example adding CO2 cools a mixture most other gases increase the temperature so the control loops must cope with this. The commissioning window of the whole system – electrics and software was only 4 days Friday to Monday with filling to resume on Tuesday.

Summary:

This project was a unanimous success and resulted in all objectives being met. The systems & knowledge developed are valuable to all projects that require very flexible recipe handing, short downtime / changeover and full offsite simulation.